@71_340 it's basically the same idea as the Ford keyless entry system, put it a code and it will unlock the doors. It comes with 3m adhesive tape so you can mount it where you want. The place the dealer will try to mount it wasn't a great spot in my mind so I just asked the dealer to program it and not mount it, so I could find the best place. I ended up putting it on the inside of my gas tank lid so it's not seen. It is a sealed unit and they say you will get 3 to 4 years of life out of it before the battery goes out. Once the battery dies you just replace the whole unit. It does require the dealer to program it for it to start working but for me I like the convenience as I'm in the airport every week and dont want to travel with my keys so I leave them in the truck. The one downside is if you leave your keys in the truck you cannot remote start through the GMC app. I got mine through a dealer who uses eBay but here is a link to one: 84182981 GM Keyless Entry Keypad | GM Parts Store